Negative pressure accessory system



Sept. 4, 1934. E, Q o d r AL I 1,972,842

NEGATIVE PRESSURE ACCESSORY SYSTEM Filed Jan. 2, 195 2 Sheets- Sheet 1 ss4, v

Sept. 4, 1934. E. c. HORTON El AL 7 NEGATIVE PRESSURE ACCESSORY SYSTEM Filed Jan. 2, 1931 2 Sheets-Sheet 2 v Flag 4,4-

I 9 H gn-ucnl'ots .H 12119 flileber drum M11 Patented Sept. 4, 1934 UNITED STATES NEGATIVE PRESSURE AccEssonY SYSTEM Erwin c. Horton, Hamburg, and Henry Hueber, Buffalo, N. Y., assignors to Trico Products Corporation, Buffalo, N. Y.

Application January 2, 1931, Serial No. 506,230 9 Claims. (01. 123-439) The present invention relates to suction pumps, and more particularly to auxiliary means therewith for sustaining the degree of suction or negative pressure that is created in the intake manifold of internal combustion engines or other source. p Automobile accessories including fuel pumps nor lifts are commonly actuated by the difference in fluid pressure between that maintaining in the atmosphere and that inthe intake manifold or other part of the engine of the automobile. Because of the varying conditions of speed and load imposed upon the automobile and its engine, such pressure. differential is likewise subject to great variation, the pressure difference being usually greatest when the engine is under light load or traveling at low speed, the throttle then being substantially closed, and lowest when the throttle is wide open! As a, result when the vehicle is have comprised a cylinder and a piston movable therein by the vehicle engine to effect a rarefaction of the gases in the suction line during periods of low pressure differential, and means to' automatically cause the device to become ineffective during periods of normal pressure. Due'to the inertia ofthe valves in such augmenting means, which caused slight delay in the opening and closing movements thereof, anddue to the high speed of oprationfand the resulting frequency of reversals of direction of the piston of such means, the degree of suction maintaining at the vacuum operated accessory was susceptible b of fluctuation resulting in the case of asuction operated fuel pump, in slightly impaired 'pumping efficiency and relatively heavy shocks to the pump elements. I

It is among the purposes of the present invention to provide a suction augmenting device of simple and durable construction which will be rendered effective, by rotation of the engine cam shaft or other part, to augment and intensify the suction or difference of pressure between the atmosphere and that maintaining in the operating line of a suction operated accessory when such.

augmentation is necessary. Meansare contemplated by the invention for decreasing to a. negligible degree the fluctuations in the degree of suction in such line whereby the accessory action will be more uniform, eflicient and .suflicient to meet the demands imposed upon it. The pressure fluctuation decreasing means also functions to reduce the force of impact between the mem: bers of the suction augmenter which-are engageable and disengageable to effect the commence ment and discontinuance of'the augmenting function of the device. I

These and other objects and advantages will become apparent from a perusal of the following description of a typical device embodying the principles of our invention, reference being made tothe accompanying drawings wherein,:

Fig. 1 is a side elevation of a fuel feeding system including a suction operated fuel lift and the suction augmenting device, these elements being illustrated as applied to the fuel intake, parts of a motor vehicle en gine;

Fig. 2 is a transverse sectional view taken through the center of the suction augmenting device, the, vehicle engine casing and operating or cam shaft being shown in operable association. therewith;

Fig.3 is a vertical section taken along line 3--3 of Fig. 2; v

Fig. 4 is a disassembled elevational view of the .casing' section of Fig. 3 as it appears when viewed in the manner indicated by the line 44 of Fig. 2;

- Fig. 5 is a view similar to Fig. 4 and showing the adjacent casing section when viewed as in-, dicated by line 5-5 of Fig. 2;

Fig. 6 is adisassembled view of the casing section. of Fig. 5 when viewed from the opposite side thereof;

Fig. 71s a valve seat and retainer element adapted to be assembled with the casing section of Fig. 6; and

Fig. 8 is a section taken along the line' 8-'-8 indicated in Fig. 6, depicting the valve seat and retainer element in assembled relationship. Fig. 9 is a fragmentary vertical section taken along line 99 of Fig. 5. j s

As shown in Fig. 1 the motor vehicle engine 10 is, as according to conventional practice, provided with a carburetor 11 for mixing air; and fuel into a combustible vapor which is drawn into the en-.' gine cylinders through an intake manifold 12. A' suction operated fuel pump or lift 13', preferably. .105

of the type shown in our co-pending application which is usually disposed at the rear of the chas-jlm sis. The fuel is drawn by suction into the pump 13 through a supply line 14 and is expelled by pressure means into the carburetor 11 through a line 15.

The lift 13 is actuated by suction maintaining in the manifold 12, Which is induced into the lift through a pair of suction lines 16 and 17 which are respectively connected to the manifold and lift, and between which the suction augmenting device 18 is attached. The latter is mounted upon the engine crank case 19, as shown in Fig. 2, adjacent to a cam 21 which is formed upon the engine cam shaft 22 or other rotating element.

The pressure augmenting and sustaining device 18, as depicted in the drawings herewith, consists of a cylinder casing 24 having a cylindrical chamber 25 therein. The casing is provided with a flange 40 for securement against the engine operating with a recess in the crank case 19, and has a vent Er passage 27 cocommunication between the int rior of the engine due to the compression'of air in the well.

casing 19 and the cylinder 25. Within thecylinder is disposed a pusher disk or drive member 26 that is mounted upon a drive rod 28 that extends through the casing 24. The rod 28 is preferably provided with an enlarged head which retains a cupped sleeve 29 slidable in a bore in the casing 24, the sleeve being held against the rod head by a coiled compression spring 31. A vent passage 30 is provided in the casing 24. between the spring well and the cylinder 25 to avoid losses Movement is imparted to the rod and sleeveby a drive tappet 32 that engages the head of the rod 28 and the cam 21, the latter rotating when the engine is operating. During one'half of each such rotation the cam, through the tappet 32, will force the .rod 28 outwardly, or 'to the right'as viewed in Fig. 2 against the compression of the spring 31,; such rotation, the rod 28 will be moved inwardly by the spring 31, which will retain the tappet in constant contact with the cam.

A cylinder head casing section 33 closes the cylinder 25, being secured to the casing 24 by bolts 20. The latter also engage a cover member34 which forms with the section 33 a vacuum capacity chamber 34" of relatively large volume as compared with the cylinder 25. A piston 35, including a cushion .36 and a packing cup 37, is fitted within the cylinder and is normally held in contact withithe plate 26 by the pressure of a coiled compression spring 38. The latter is seated in an annular well 39 formed in the section 33 and'is centered relative to the piston by a' centering button 41 formed with the piston.

42 communicating with the cylinder 25 through a port 44 asshown in Fig. 6, in Fig. 8 and in Fig. 9.

A port 45 extends through the casing section 33 between the cylinder'25 and the chamber 34'.'

Ports 44, 45am provided with valves 46, 47 respectively, a plate 48, depicted in Figs. 7 and 8, being fitted in a recess 49 in the head casing wall for retainingthe valves. Valve 46 is adapted to seatagainst the plate 48 covering an opening 51 formed therein and the valve 47 is adapted to close against a seat 52 to prevent passage of fluid through the plate apertures 53 and port 45.

The valves comprise light disks which are read.-

c sing end to open rocate with the rod 28 and plate 26,

During the remaining half of each ily movable from open to closed position or vice versa by the impingement of air or other fluid thereagainst. In normal operation, with the engine moving under normal throttle opening, the difference between the pressure of the .atmosphere and that maintaining in the intake manifold 12 will be sufficient to operate the pump or lift 13. During such a period air under less-thanatmospheric pressure will be drawn through the tubes 16 and 17 into the manifold 12, the path of movement thereof being through tube 17, passage 43, chamber 34', port 45, cylinder 25, port 44 and 'tube 16. The pressure maintaining on the outer side of the piston 35 (to the right as shown in Fig. 2) is sufliciently less than that on the pposite side thereof, so that the piston will be moved to its outward limit position against. the pressure of the spring 38. Movement of air through the augmenting device will cause both valves 46, 47 to remain unseated.

The reciprocating movement of the rod 28 and the attached plate 26, effected by the rotation of the cam 21 and the pressure of the spring 31 will,

. under such normal conditions, not affect the piston 35 which will be held outwardly beyond the suction, or a slight lessening of the pressure differential by which the accessory 13 is actuated force the piston inwardly (toward the left as I viewed in Fig. 2) causing the piston to engage the drive'plate 26. Thereafter, until the, normal degree of suction within the chamber and line 1'? has been again developed, the pistia will recipe spring 38 retaining the piston in contact with the plate. During this phase of operationthe piston 35 on inward movement under the urge of spring 38, will draw air from the chamber 34' into the'cylinder 25 through the port 45, the valve 47 unseating and. the valve 51 seating to close communicationbetween the line 16 and the cylinder. Upon outward movement of the piston, against the pressureof the spring 38, air will beforced from the cylinder into the exhaust line 16, the valve 4'7 being seated and the valve 51 unseated by the fluid in motion.

vment of the piston 35 or by reason of a drop of pressure in the intake-manifold, the atmospheric pressure upon the inner face of the piston will oppose the spring 38 and force the piston to a position where it will not be operably engaged by the plate 26.

It will be understood that while the piston is in reciprocating movement, and at other times,

atmospheric pressure will maintainin the cylin- .der 25 inwardly of the piston: due to the vent opening to the crank case interior provided by the passage 27, the recess in the inner end of the casing section 24 as shown in Fig- 3, and the opening in the crank case shown in Fig. 2. The vent passage will alsofunction to admit lubricating spray from the crank case to the cylinder 25. Chamber 34' being of large capacity will maintain an operating degree of evacuation for a considerable time, and when the fluid pressure does increase beyond this necessary degree, the rate of increase will be gradual, allowing the piston 35 to move slowly inwardly to engage the 1 When a sumcient degree of evacuation has been Y reciprocating plate 26 in order that the piston may engage the plate when the latter is near the end of its inward stroke and consequently moving slowly. The force of impact of these parts is thereby reduced to a minimum, greatly ing drive element therein, a piston movable in said casing, a resilient member for urging said piston into contact with said reciprocating drive element, a capacity chamber in communication with said cylinder, check valve means for passing fluid from said capacity chamber to said cylinder, and check valve means for passing fluid from said cylinder, whereby upon increase of pressure in said capacity chamber said resilient member may become effective to urge said pis ton into engagement with said drive element to draw fluid from said chamber.

2. In combination with a fuel feeding system for an engine having an intake manifold, a suction operated fuel lift and a suction line between said manifold and lift, a capacity chamber associated with said suction line, a cylinder casing communicating with the capacity chamber and suction line, a piston movable therein, drive means adapted to effect reciprocation of said piston only when the fluid pressure in said chamber rises above a predetermined normal, and

valve means whereby movement of fluid from said ciation of said element and'means when said pressure falls below a predetermined pressure, and valve means for causing said element to withdraw fluid from said chamber when in operable association with said drive means.

4. A suction augmenter for a suction line, comprising a cylinder having valved inlet and outlet ports, a piston freely reciprocatory in the cylinder, means urging the piston in one direction of movement, a drive member separate from and engageable with the piston to move it in the opposite direction, and a capacity chamber communicating with the suction line and with said cylinder through said valved inlet port, whereby movement of said piston into engagement with said drive member upon increase of .pressure in said suction line will be retarded.

5. An automotive vehicle having an engine, an intake manifold for the engine, a suction operated accessory, a cylinder having a movable said capacity chamber for urging the disk into operative relationship with said actuating means, and a conduit communicating with said manifold, accessory and capacity chamber.

6. A device for augmenting suction in a suction line, comprising a cylinder having a piston movable therein, a cylinder head ha' ing valved inlet and outlet ports and a capacity chamber therein, said'capacity chamber communicating with said cylinder through said inlet port, resilient means for urging said piston away from said cylinder head, and actuating means free of and engageable with said piston to urge it toward said head, whereby said piston may be held out of engagement with said actuating means against the urge of said resilient means by a vacuous condition in said cylinder adjacent said head and in said capacity chamber, and whereby upon lessening of said vacuous condition in said portion of said cylinder-said capacity chamber will function to retard movement of said piston into engagement with said actuating means.

7. In combination with an internal combustion engine intake manifold and a suction operated accessory, of a suction booster pump having a valved outlet connected directly to the manifold, said pump having a head provided with a chamher, said pump having an inlet leading from the chamber, and said chamber itself having an inlet leading from the accessory, one of said inlets beingvalved for cooperating with the valved outlet in directing a uni-directional air flow through the pump from the accessory.

8. In a suction producing apparatus associated with a suction line extending to a suction operable device, a cylinder chamber and a piston movable therein for enlarging and contracting said chamber, a check valved inlet passage opening into the chamber and a check valved exhaust passage leading therefrom, a capacity chamber communicating with the check valved inlet passage where- 5 by fluid may pass from the capacity chamber into the cylinder chamber, a fluid passage for connectirig said capacity chamber to the suction line, drive means adapted to engage and actuate said piston, and meansfor causing said piston to 133 engage said drive means for actuation thereby when the fluid pressure in said capacity chamber exceeds a predetermined degree.

9. In combination with an internal combustion engine intake manifold and a suction operated 135 accessory, a cylinder chamber and a capacity chamber, a check valved passage for permitting fluid passage from the capacity chamber into the cylinder chamber, a check valved connection between the cylinder chamber and the intake mani- 

